The pH Optima for Papain and Bromelain Treatment of Red Cells

The action of papain and bromelain, prepared over a pH range from 4.6 to 8.6, was evaluated for the ability to render red cells agglutinable by five incomplete antibodies of differing blood group specificities using a two-stage technique. The optimal pH for treatment of red cells by activated papain or bromelain was between 5.4 and 5.8. Above this pH range, a fall in serological sensitivity was apparent which was much more pronounced with papain than with bromelain. The optimal pH for enzyme treatment of red cells can be achieved in two-stage techniques, but not in one-stage techniques due to the buffering effect of serum proteins.     

Malaria resurgence in India: a critical study

In 1953, the Indian National Malaria Control Programme (NMCP) was started. Encouraged by the results, and the fact that insecticide resistance in vector species may evolve and become an obstacle, in 1958 a control programme was converted to the National Malaria Eradication Programme (NMEP). By 1964, malaria was eradicated from 88% of the area and it was in the advanced stage of spraying in the remaining parts. At that time, focal outbreaks that occurred in 1965 and increased in later years, could not be contained due to the shortages of DDT. As a result, large areas in consolidation and maintenance phases were reverted to the attack phase. Besides, the infrastructure in general health services was not adequate and mature enough to take up surveillance and vigilance. This produced a large number of secondary cases due to the re-introduction and relapse of malaria. Added to this was the problem of urban malaria, the control of which was the responsibility of local bodies. Malaria cases increased in towns, and started diffusing to the rural areas, due to inadequate staff and the shortages of malarial larvicidal oil (MLO). Later, it turned out, that while it was technically feasible to eradicate malaria from 91% of the population, the strategy of indoor spraying of DDT to interrupt transmission did not succeed in 9.0% of the population, despite more than 12-14 years of regular spraying. During the years of resurgence, there was no research support to the programme, so that technical problems were not properly appreciated, understood and tackled. The reservoir of parasites that were present throughout the country started multiplying and spreading to newer areas due to the presence of vectors in high densities. Thus malaria resurged and re-established itself even in areas that were at one time freed from the disease. The analysis of the pattern of malaria resurgence revealed that malaria outbreaks preceded the true problem of insecticide resistance. It is noteworthy to mention that malaria resurgence occurred in towns where the control measures were non-insecticidal and in regions which were not under the influence of insecticide-resistant vectors. The study also revealed that resurgence occurred before the introduction of high-yielding varieties programme in the country, and had no relationship to either the cotton or rice growing or intensive agriculture.     

Theoretical calculation of relative binding affinity in host-guest systems.

The relative free energy of binding the anions Cl- and Br- to the macrotricyclic receptor SC24 in water has been computed by a computer simulation technique. This result and an incidental result for the relative free energy of hydration of the anions are in excellent agreement with experimental data. The simulation approach to ligand-receptor interactions that is described here has significant potential as a predictive tool in chemistry, biochemistry, and pharmacology.     

Three-dimensional computed tomographic analysis of the normal temporomandibular joint

Ten temporomandibular joints, obtained from three asymptomatic patients and two cadavers, were examined by three-dimensional computed tomography. The osseous components of the condylar process of the mandible and the glenoid fossa of the temporal bone were well visualized. The meniscus was visualized in both the closed- and the open-mouthed positions. Advantages and disadvantages of the technique are discussed.     

Influence of mesh materials on collagen deposition in a rat model.

Alterations of the extracellular matrix (ECM) with its major component collagen are increasingly discussed as possible risk factors implicated in the development of abdominal-wall herniation. Because of the widespread use of alloplastic meshes for the surgical repair of hernias, an animal study was performed to analyze the influence of various mesh materials on the quantity and quality of collagen deposition. In 60 male Sprague-Dawley rats an abdominal replacement was performed using three different kinds of mesh materials: polyester (PE), a pure polypropylene (PP), and a composite mesh made of polypropylene and polyglactin (PG). A simple fascia suture repair served as control. The count of fibroblasts, the collagen/protein ratio, the type I/III collagen ratio, and the expression of basic fibroblast growth factor (b-FGF) at the interface were analyzed after 7, 21, and 90 days. The ratio of collagen to overall protein (microg/mg) showed significant differences comparing different mesh materials (sham controls 38.44 +/- 16.33 microg/mg, PE 68.5 +/- 23.8 microg/mg, PP 101.6 +/- 32.3 microg/mg, PG 49.6 +/- 11.6 microg/mg at day 90). The ratio of collagen type I/III increased over time in all groups. However, 90 days after mesh implantation the ratio was always significantly lowered compared to the controls. No significant difference was found comparing different mesh materials. The alteration of the scar composition is closely connected to an increased b-FGF expression. b-FGF and count of fibroblasts highly correlated (r =.95) and showed significant elevated levels compared to simple suture repair. The results of our study strongly support the notion that wound healing is affected by mesh implantation. The quality of the ECM deposition as determined by collagen type I/III ratio is impaired in general, whereas the quantity of ECM deposition is markedly influenced by the kind of mesh material.     

Changes in bone structure and mass with advancing age in the male C57BL/6J mouse.

To determine whether the mouse loses bone with aging and whether the changes mimic those observed in human aging, we examined the changes in the tibial metaphysis and diaphysis in the male C57BL/6J mouse over its life span using microcomputed tomography (microCT). Cancellous bone volume fraction (BV/TV) decreased 60% between 6 weeks and 24 months of age. Loss was characterized by decreased trabecular number (Tb.N), increased trabecular spacing (Tb.Sp), and decreased connectivity. Anisotropy decreased while the structure model index increased with age. Cortical bone thickness increased between 6 weeks and 6 months of age and then decreased continuously to 24 months (-12%). Cortical bone area (Ct.Ar) remained constant between 6 and 24 months. Fat-free weight reached a peak at 12 months and gradually declined to 24 months. Total mass lost between 12 and 24 months reached 10%. Overall, the age-related changes in skeletal mass and architecture in the mouse were remarkably similar to those seen in human aging. Furthermore, the rapid early loss of cancellous bone suggests that bone loss is not just associated with old age in the mouse but rather occurs as a continuum from early growth. We conclude that the C57BL/6J male mouse maybe a useful model to study at least some aspects of age-related bone loss in humans.     

Methylene blue soldered microvascular anastomoses in vivo.

OBJECTIVES: solders containing chromophores and proteins enhance the strength of lasered anastomoses. Methylene blue (MB) solder anastomoses in vitro are strong but no in vivo work has been reported. We used an MB solder in vivo and studied the effects of two laser powers on patency and histological appearance. DESIGN, MATERIALS AND METHODS: two groups of 15 rabbits had unilateral end-to-end carotid anastomoses (1.5-2.0 mm) formed using three stay sutures and MB solder. Group 1 anastomoses were formed at 5.7 Wcm(-1) and Group 2 at 2.8 Wcm(-1). The vessels were examined at various points by necropsy for patency and gross macroscopic appearance, with subsequent histological examination. RESULTS: group 2 showed patency of 93.3% v 0% ( p<0.001) endothelialisation of 100% v 26.6% ( p<0.001), giant cell formation 0% v 40.0% ( p<0.01), but stenosis was not significantly different (0% v 13.3% p=0.06). Group 2 showed a higher rate of intimal hyperplasia (IH) (66.6% v 20.0% p<0.05) but neither group exhibited thermal injury or aneurysm formation. CONCLUSIONS: laser soldered microvascular anastomoses were formed in vessels of 1.5-2.0 mm with a high degree of patency. A relationship appears to exist between laser power and anastomotic patency. Methylene blue fading has the potential to act as a switch against over exposure and a visual indicator of solder activation.